Innovative “water batteries” and “sand batteries” pave the way forward for the storage of renewable energy to ensure a green, stable power system
A challenge as old as renewable energy itself
In 1910, Canadian Inventor Reginald Fessenden described concern for the commercial use of renewable energy as a “double one”, saying, “The energy of the sources must first be charged so as to be suitable in form, it must next be stored so as to be available in time.“.[i] In the latter part of his comment, Fessenden refers to the need for excess generation of power from renewable sources of energy such as solar and wind energy that cannot be relied upon to produce a constant and consistent stream of electricity at times when the sun or the wind are not at the intensity required to generate power.[ii] Intermittency has been a popular argument for those that seek to discredit the use of solar and wind energy across the globe and around the year. Self-proclaimed wind expert and former US President Donald Trump notably said, “When the wind stops blowing, that’s the end of your electric.“.[iii] Even at the time of this statement, its veracity was challenged by the American Wind Energy Association (AWEA), who pointed out that modern wind turbines can produce usable amounts of energy 90% of the time.[iv] There still remains the question of that further 10% and the question of how countries, particularly those at northern latitudes, can effectively utilise solar power in periods of low light.
Worldwide investment to tackle the storage problem hits new highs
The IEA World Energy Investment report 2022 highlights the growth in battery storage investments in the power sector.[v] Capital spending is anticipated to nearly triple in only two years as such investment in battery energy storage is now gaining the most traction in its history. Grid-scale deployment, which accounted for more than 70% of total spending in 2021, and lithium ion batteries, which accounted for more than 90% of all installations in 2020 and 2021, are the two factors driving this trend.[vi] With China aiming to have 30 GW of non-hydro energy storage capacity by 2025 and the United States having more than 20 GW of grid-scale projects either planned or under development, the pipeline of projects is vast.[vii] Other markets, including those in Europe, Korea, Japan, and Australia, are also seeing growth in this industry.
Swiss water battery at Nant De Drance
For 14 years, Switzerland has been developing what has been described as an “important tool for stabilising power supplies in Switzerland and Europe”.[viii] Costing €2 billion and located 600 metres beneath the Swiss Alps, Nant De Drance can store enough energy to power 900,000 homes.[ix] The plant began operating on the 1st of July, and the site will be inaugurated in September with a celebration that will see students from the surrounding Trient Valley invited to explore the plant as a symbolic nod to the generational value that the project will add to Swiss and European energy resilience.[x]
Construction of rotor at the Nant De Drance site
Source: Nant De Drance
A Press release from Nant De Drance stated, “In face of the growth of new renewable energies such as wind and photovoltaic whose production is intermittent; this flexibility is required to compensate for the fluctuations on the electric grid and maintain continual equilibrium between production and electricity consumption. Nant de Drance works like a gigantic battery which allows excess electricity to be stored in a short term or to produce the necessary energy when demand exceeds production”.[xi]
So too solar storage takes steps forward
In collaboration with Vatajankoski, both based in Finland, Polar Night Energy are pioneering the development of sand-based thermal energy storage. This process sees the diversion of power and transfer into heat energy, this heat energy is stored in “sand batteries” at temperatures of up to 500℃.[xii] Heat storage in this way can utilise power from periods of overgeneration from wind and solar energy in colder periods where it can be used to heat homes.[xiii] Markku Ylönen, a founder of Polar North Energy, commented, “Whenever there’s like this high surge of available green electricity, we want to be able to get it into the storage really quickly,“. In these colder periods, it is common for electricity to be more expensive. In this light, solutions like this, pending successful pilot schemes, could provide an elegant solution not only to limits on gas supplies, traditionally used to heat homes across Europe, imposed by Russia but also to the cost-of-living crisis seen closer to home.[xiv]
Sand Battery Installed at Finnish power plant Vatajankoski
Source: Polar Night Energy
A resilient future is a green future
Particularly in Europe, the development of resilience in the renewable energy sector is noteworthy, especially in the sharp relief into which it is thrown by the crisis in Ukraine. The scales may now be tipping in favour of renewables over traditional fossil fuels when it comes to reliability and resilience.
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